[libvirt-users] which vols added to storage pool during refresh?

[Daniel P. Berrange]

On Wed, Aug 17, 2011 at 10:36:26AM -0700, Gareth S Bestor wrote:
> As you can see, this pool maps to /dev/disk/by-id. There may be a large 
> number of actual volume entries in /dev/disk/by-id, however it appears 
> only a distinct subset of them are actually added into the libvirt pool 
> when you do a pool-refresh. What does libvirt check when determining 
> which, and whether or not, to add one of these volume into the vol-list? 
> 
> In particular, we have a case when one specific volume in /dev/disk/by-id 
> is *not* added into the pool, and no amount of pool-refresh makes a 
> difference. We did notice that if you remove all the sym links in 
> /dev/disk/by-id and do a pool-refresh, that libvirt re-scans the bus, 
> recreates the links in /dev/disk/by-id, and adds (some of) the volumes 
> back into the vol-list. But not this one problematic vol, so clearly there 
> is something about this vol that libvirt doesnt like and why it is 
> (deliberately?) not added to the pool. 
> 
> What checks, etc does libvirt make against vols when determining whether 
> to add them to a pool? 

If we have an error processing any volume, that will be skipped. There
is one non-error related check though, that may cause a volume to be
skipped:

    /* We don't create volumes for devices other than disk and cdrom
     * devices, but finding a device that isn't one of those types
     * isn't an error, either. */
    if (!(device_type == VIR_STORAGE_DEVICE_TYPE_DISK ||
          device_type == VIR_STORAGE_DEVICE_TYPE_ROM))
    {
        retval = 0;
        goto out;
    }

What value is in 

   /sys/bus/scsi/devices/XXXXX/type

for the LUN in question ?  And is that value different for all the
other LUNs in that HBA ?


Daniel
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